Disposal leak, replacement, potential can o worms

Hi All,
My Badger 5 is leaking from a hole in the housing. Grrr. I have a new Badger 5 in a box, begging to be installed. Only for aesthetics, I would like to change the basket strainer on the sink side and maybe change the strainer on the Badger side, too. My plumbing is pretty old, but working. Based on my pictures, would you guys change everything out to PVC or should I let sleeping dogs lie and JUST change the Badger? I'm also enclosing the picture of the next door condo's kitchen. If you guys suggest I redo everything, is that a good example?
Thanks!

When you get the plumber in, have him rebuild that mess with plastic pipe, as it tends to transmit less noise than metal. This is important
with the infamous Badger 5. Then get with your condo officials and ask why neither you nor your neighbor have sanitary, code-compliant
drainage facilities. Suggest that if they do not fix the situation at their expense, you may have to call in the city/county/state/whatever
plumbing inspector.

Here's the deal. Most, if not all condo associations require all plumbing and electrical work to be done by a licensed and bonded plumber/electrician. You are not allowed to DIY any of that. So, best advice is go to the condo board with this. Don't do any more work yourself. It is absolutely certain that this work was not done by a plumber, not even a half decent handyman. It might be wise to check with other condo owners and see if their plumbing is the same.

Unless BOTH installations have the "P" trap under the floor, which is a different can of worms, neither installation is correct, OR "safe". BUT, you would have to know whether it is or is not there before you can even think about doing it "correctly".

Thanks guys!
These were built as apartments in '69 and converted to condos in '79. I only know about the last fifteen years.

The pictures are of two adjacent first-floor condos. Moreover, I spoke with four other neighbors and they have the exact same layout. Of course, everyone notices that one sink 'acts' as a vent for the other sink, and everyone wishes for the accessibility of a p-trap for jewelery or whatever. One neighbor just had his whole condo remodeled and he got a one-bay sink. He notices it drains a lot more slowly than when he had a two-bay sink.

The p-trap is underneath the floor. It flows three feet to a wall at the end of the kitchen that contains a big cast iron drain pipe and a galvanized steel air stack. These tie into the upstairs condo, correspondingly.

The condo with the pvc was done by a licensed plumber back in 2003, or so. That unit had a collapsed(?) wastewater line and the foundation was jackhammered and new pipes were put in.

The condo with the steel pipes is mostly original. The instant hot water heater was installed by a licensed plumber in 2001. I think he intercepted the electrical line and added the switch (far left in the picture) for the disposal and the outlet (bottom middle) for the heater. That water tank rotted out and a new hot water heater was installed by a different licensed plumber in 2010. I'm not sure if the Badger is from the 1980 condo conversion.

So, except for putting in a new Moen cartridge in the faucet myself, the layout has only been touched by licensed plumbers. It seems that just about everything in these old condos is grandfathered, for better or worse.

Unfortunately, nothing is coming out of the HOA's expense. It's coming out of my pocket; and my pocket's got holes.
What do you guys suggest? I mean, it does function okay, except for the hole in the Badger's casing. Thanks, again.

One sink does NOT act as a vent for the other one, OR the "P" trap, BUT, it does allow the air trapped in the vertical pipe to escape. That does not happen with a single sink which is why it drains slower.

Okay, the Badger finally blew up. I replaced it. Except for the faucet's cartridge, it is the ONLY job that I have done to this kitchen. Everything else is original or has been done by licensed plumbers. I replaced the Badger EXACTLY to the instructions and touched nothing else.

I am set to get a new counter-top and would like to get a plumber in there to get everything sorted beforehand. Besides getting a new sink, basket strainers, faucet, instant hot water heater, and lines, I would also like to take the opportunity to replace the almost fifty year old rotting metal pipes with new ones. Oh, I would also like for the Badger to not spew a geyser of water from the adjacent sink every time I use the disposal (every six weeks).

The old one also geyser-ed up the adjacent sink, so that's not unique to the new Badger. Either sink drains very slowly if the adjacent sink has a stopper. Is it possible that the vent pipe that runs up to the roof is clogged? Is that something that I should mention to the plumber?

A plumber from the contracting company the HOA uses advised me that he would NOT install a second p-trap under the sink, as there is one already under the slab. He cited some siphoning issue that could arise. He suggested doing exactly what is shown in the second picture (the white pvc).

Is he right? From what you guys tell me, that would be a NO. I'm thinking of going with a different plumber, but I would like to know what you guys suggest would be the proper solution.

The tee on the opposing bowl needs to be a baffle tee. A tee without the baffle will always do that. It's not the disposer, it's the tee.
You have no p-trap there. That means sewer gas is coming up from both bowls. Your kitchen will smell so much better if you fix that.
Me myself, I perfer the smell of fresh food cooking, not the stench of old rotting food. Just saying, it will make a huge difference.

The "P" trap is probably under the floor, his new disposer may have come with line cord and plug. HE is giving you the correct information considering how the piping was originally installed, although that cleanout plug will probably be useless because of the P trap under the floor. See my previous reply as to why the sink MAY NOT drain properly if the other bowl has the strainer closed. A "double trap" will NOT cause siphoning issues. It will keep the sink from draining, similar to when you have a plug in the other bowl, but worse.

Currently, there is no baffle tee. Insinkerator did not include one, nor mention it in their instructions. I will definitely add that to the list for the plumber, though.

With the spewing, I was afraid of installing an air release. Should I add a hole for an air release system to my granite order? I never use the Badger, except to see if it runs. So, I haven't been disgusted by having waste go into the dishwasher. Still, I see why it is considered standard in modern plumbing code.

True, there is a p-trap. It's just underneath the slab. It's nerve wracking to never drop anything down the drain.

I'm guessing you guys would not install a second p-trap underneath the sink? I don't really have a problem with the drain speed in the sink, but I don't want to make it slower. It would be nice for dropped jewelry or toys, though.

Below, is a picture of how my neighbor's plumber conveniently accessed her p-trap by simply jack-hammering a hole in the foundation. One side is from her upstairs neighbor's condo and the other is downstream from her own p-trap. Sheesh.